The MOS Technology 6510 is an 8-bit microprocessor designed by MOS Technology, Inc., and is a modified form of the very successful 6502.The primary change from the 6502 was the addition of an 8-bit general purpose I/O port (only six I/O pins were available in the most common version of the 6510). In addition, the address bus could be made tristate.The 6510 was only widely used in the Commodore 64 home computer and its variants.